Fuel injection control method and fuel injection control apparatus for engine

Abstract

In a fuel injection control method of an engine, an electronic control unit calculates a pressure integrated value for one combustion cycle by detecting a combustion cycle and continuously detecting a suction air pipe pressure and determines that the engine is under an accelerated state such that a pressure difference determined by comparing the pressure integrated value with the pressure integrated value at the preceding combustion cycle becomes equal to or more than a predetermined acceleration determining reference value, thereby increasing a fuel amount. The electronic control unit determines that the engine is under the accelerated state at a particular time when the difference between the pressure integrated value and the atmospheric pressure becomes equal to or less than a reference value and a pressure difference integrated value obtained by integrating each of the pressure differences within an integrating period becomes equal to or more than another reference value.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method of executing a fuel injection control by detecting an acceleration state of an engine, and a fuel injection control apparatus, and more particularly, to a fuel injection control method and a fuel injection control apparatus which determines an acceleration state at a predetermined level or more for executing an accurate air-fuel ratio control so as to execute a fuel injection control. [0003] 2. Description of the Related Art [0004] In recent years, a fuel supply system of an engine is generally provided with a fuel injection control apparatus and controlled in such a manner as to inject a fuel in correspondence to an air amount sucked into a combustion chamber on the basis of data detected by various monitors. However, in a transient state such as a rapid accelerating time or the like, it becomes frequently hard to keep an air-fuel ratio of an air-fuel mixture optimum due to...

AI Technical Summary

Benefits of technology

The present invention provides a method and apparatus for fuel injection control in an engine by detecting fluctuations in suction air pipe pressure to determine acceleration state. This allows for optimal air-fuel ratio control without increasing cost. The method involves calculating a pressure integrated value for one combustion cycle and detecting a pressure difference between the integrated value and the atmospheric pressure. The pressure difference is then compared with a predetermined acceleration determining reference value to increase fuel amount. The apparatus includes an electronic control unit and an atmospheric pressure detecting means to accurately determine the accelerated state. This method and apparatus can be easily incorporated into existing fuel supply systems of 4-cycle engines to achieve appropriate air-fuel ratio control.

Problems solved by technology

However, in a transient state such as a rapid accelerating time or the like, it becomes frequently hard to keep an air-fuel ratio of an air-fuel mixture optimum due to a detection delay of a suction air amount and a time lag until a feed of the fuel injected into a suction pipe reaches a combustion chamber.

However, if the throttle opening degree sensor is provided in a fuel supply system, a manufacturing cost is largely increased, so that the structure tends to be disadvantageous in a view of a cost.

Accordingly, there is a defect that an amount of the fuel is not increased and the air-fuel ratio becomes lean, so that a trouble such as a breathing or the like is generated.

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